rpi-4.19.y-rt update for Pi 4 8GB

[gtrainavicius]

Hey, looks like a kernel built based on rpi-4.19.y-rt branch boots, but the USB drivers at least don't work, and users report the system after restart is unable to boot.

Switching to mainline kernel and installing all package updates from apt-get fixes the issue.

Any ideas what needs to be done for rpi-4.19.y-rt branch for it to work well with Pi4 8GB?

[timg236]

It's probably missing the VL805 changes or the PCI fundamental reset patch
https://lkml.org/lkml/2020/5/5/1003

https://lkml.org/lkml/2020/5/7/1056

[gtrainavicius]

I've tried applying these changes to 4.19.y-rt branch and they do solve the problem. Are these changes in this source repository's 4.19.y branch? I don't see the same patches applied here.

[gtrainavicius]

ping :)

[pelwell]

See c74b1b5 and https://github.com/raspberrypi/linux/blob/rpi-4.19.y/drivers/pci/controller/pcie-brcmstb.c#L1416.

[gtrainavicius]

Ok, thank you, I was looking for the changes in raspberrypi.c as in the previous links. :)

[pelwell]

The fact that the rpi-4.19.y kernel has working USB on an 8GB Pi4 (R6, rev 1.4) is a big clue that this issue has been solved there.